Schweitzer Engineering Laboratories SEL-387E - SECTION 1: INTRODUCTION AND SPECIFICATIONS; Relay Functions

Date Code 20080110 Introduction and Specifications 1-1
SEL-387E Instruction Manual
SECTION 1: INTRODUCTION AND SPECIFICATIONS
I NTRODUCTION
Use this relay to protect two- to three-winding power transformers, buses, reactors, generators,
large motors, or other multiterminal power apparatus. Three- or four-terminal applications
permit separate connection of current transformers from two breakers connected to the same
transformer winding, such as in ring-bus or breaker-and-a-half schemes. The relay settings
permit you to use wye- or delta-connected current transformers with virtually any type of
transformer winding connection.
The SEL-387E Differential Relay provides three differential elements with dual slope
characteristics. The second slope provides security against CT saturation for heavy through
faults. Be sure to conduct detailed analysis of CT performance under worst-case saturation
conditions to set the relay characteristic correctly for bus protection applications. For assistance
with CT selection, obtain SEL Application Guide 99-07 Bus Protection Using a Four-Winding
Low-Impedance Percentage Differential Relay from the SEL Web site (www.selinc.com).
I NSTRUCTION M ANUAL O VERVIEW
This instruction manual applies to the SEL-387E Relay. If you are unfamiliar with this relay, we
suggest that you read the following sections in the outlined order.
Section 1: Introduction and Specifications for an introduction, instruction manual overview,
relay functional overview, and specifications.
Section 3: Protection Functions to understand the protection elements and their associated
settings.
Section 4: Control Logic to understand inputs, the Relay Word, outputs, and logic. Use this
section to understand the settings necessary for implementing your logic.
Section 6: Setting the Relay to understand settings that are not described in Section 3 or
Section 4, for default settings, and for settings sheets.
Section 7: Communications for a description of the serial port commands used to set the relay
for control, obtain target information, and obtain metering information, etc.
Section 8: Front-Panel Operation for a description of how to perform the serial port commands
from the front panel.
Section 5: Metering and Monitoring to learn how to retrieve operations data such as metering,
DC battery monitor, breaker monitor, and relay status.
Section 9: Analyzing Events for a description of event report and sequential events report
generation, event report formats, sequential event reports, and report interpretation.